There is a library device that accommodates a plurality of recording medium cartridges (for example, magnetic tape cartridges) and performs processing such as reading and writing of data from/onto a recording medium cartridge selected from the plurality of recording medium cartridges (see, for example, Patent literatures 1 and 2). In such a library device, a magazine is accommodated in a housing so as to be able to be put in and out, and a plurality of recording medium cartridges are accommodated in the magazine so as to be able to be put in and out. In addition, in the library device, when a recording medium cartridge is selected, the selected recording medium cartridge is ejected from the magazine, the ejected recording medium cartridge is conveyed to a recording medium driver, and processing such as data reading and writing is performed against the selected recording medium cartridge in the recording medium driver.
When loading the library device with the recording medium cartridge, a user first loads the magazine with the recording medium cartridge, and then loads the housing with the magazine loaded with the recording medium cartridge. When loading the housing with the magazine, there is a possibility that the recording medium cartridge loads the magazine in an incomplete state. At this occasion, when vibration or the like is added during loading, the recording medium cartridge may jump out of the magazine by a spring in the magazine after the magazine has been loaded in the housing. When the library device is used in a state where the recording medium cartridge has jumped out of the magazine in the housing, the jumped out recording medium cartridge comes into contact with the one (for example, an accessor, a cartridge tunnel) located inside the housing, and the selected recording medium cartridge cannot be ejected from the magazine. Also, when the recording medium cartridge stays in the housing in a state jumped out of the magazine, it is impossible to eject the magazine. Furthermore, when the recording medium cartridge completely drops out of the magazine in the housing, the magazine can be ejected, but the dropped out recording medium cartridge stays in the housing.
Therefore, in order to prevent a recording medium cartridge from jumping out of a magazine, a library device having a cartridge jump-out preventing mechanism for preventing a recording medium cartridge from jumping out of a magazine by using a stopper member (see, for example, Patent Literature 1) and a cartridge automatic exchanging device having a mechanism for pushing back a cartridge by using a tapered low friction member (see, for example, Patent Literature 2) have been proposed.